Chan Trading operates in a large town area. Currently, Chan has its own factory to produce butter cookies. The unit cost to produce the butter cookies are as follows: $ 0.4 Raw materials Direct labour Variable overhead 0.5 0.3 Fixed overhead 0.6 Total 1.8 Fixed overhead is detailed as follows: $ Avoidable fixed overhead Depreciation of equipment $ 2,000 1,000 A local manufacturer has offered to supply Chan all the butter cookies it needs. Its price is $1.70. If the offer is accepted, the equipment used by Chan would be scrapped (it is old and has no market value). Chan produce 5,000 butter cookies per month. Question: Analyze and determine whether Chan should continue to make its own butter cookies or to purchase from the external supplier